Illustrations by Ruth Basagoitia
Ovarian cancer is a kind of cancer that begins in the ovaries. People born of the female sex are usually born with two ovaries, one on each side of the uterus. Ovaries are small — about the size of an almond — and they’re responsible for many reproductive functions.
Ovarian cancer can be very difficult to detect and diagnose, as many of its symptoms are similar to those caused by far less serious problems, like indigestion and bloating. There are often no signs or symptoms of early ovarian cancer, and some cases aren’t diagnosed until the cancer has spread to the abdomen or another part of the pelvis.
Ovarian cancer that has progressed beyond the ovaries is very difficult to treat. That being said, when the cancer remains in the ovaries, doctors have a better chance of treating it successfully with surgery and chemotherapy.
Types of ovarian cancer
There are over 30 kinds of ovarian cancer, and they’re classified by the cell type from which they begin. Ovaries are made up of three main kinds of cells:
- epithelial tumors
- stromal tumors
- germ cell tumors
Epithelial tumors can be either benign, or very dangerous. About 90 percent of ovarian cancers are epithelial tumors. They form on the outer layer of the ovaries.
This kind of ovarian cancer begins in the tissue that contains hormone-producing cells. They’re also called sex cord-stromal tumors. According to the Mayo Clinic, about 7 percent of ovarian cancers are stromal.
Germ cell tumors
Germ cell tumors are a rare form of ovarian cancer that starts in egg-producing cells. They usually occur in younger people.
About 21,000 U.S. people get diagnosed with ovarian cancer every year, and about 14,000 die from it.
An individual’s lifetime risk of developing ovarian cancer is about 1 in 78. Their risk of dying from ovarian cancer is about 1 in 108.
Fortunately, according to the American Cancer Society, the rate of diagnosis has slowly decreased over the past 20 years.
Diagnosis and death from ovarian cancer has varied for people born of the female sex depending on race and ethnicity. Between 1999 and 2014, white individuals were more likely to be diagnosed with or die due to ovarian cancer than those from any other ethnic groups.
Black individuals were the next group, followed by Hispanics, Asian American and Pacific Islanders, and people of American Indian or Alaska Native descent.
There are many factors that may increase a person’s risk of ovarian cancer. However, just because an individual may fit into these categories doesn’t mean they’ll develop the disease. Below are known risks for developing the most common type, epithelial ovarian cancer:
Ovarian cancer can develop at any point in a female person’s life, but it’s rare for those under age 40. According to the American Cancer Society, half of all ovarian cancers are found in individuals aged 63 and older.
Obese individuals, or those with a body mass index (BMI) of at least 30, have an increased risk of ovarian cancer (and other types of cancer).
An inherited gene mutation may be to blame for a small percentage of ovarian cancers. The genes known as breast cancer gene 1 (BRCA1) and breast cancer gene 2 (BRCA2) have been shown to increase a person’s risk of ovarian cancer significantly.
Inherited genes aren’t the only way your family may impact your risk for ovarian cancer. If your mother, sister, or daughter had or have ovarian cancer, your risk increases.
Personal history of breast cancer
If you have been diagnosed with breast cancer, you may also have an increased risk of developing ovarian cancer.
Hormone replacement therapy
Long-term and high-dose use of estrogen hormone replacement therapy increases your risk for ovarian cancer. The risk may be higher for individuals who take estrogen alone, without progesterone, for at least 5 to 10 years.
Individuals who become pregnant and carry the pregnancy to full-term before the age of 26 are less likely to develop ovarian cancer than people who have never been pregnant. The risk is further decreased with subsequent full-term pregnancies, as well as with breastfeeding. Individuals who become pregnant for the first time and carry the pregnancy to full-term after the age of 35 have been found more likely to develop ovarian cancer. A higher risk is found in those who never carried a pregnancy to term, too.
Individuals who have undergone any type of fertility treatment have an increased risk of ovarian cancer.
Birth control use
People who have used oral contraceptives actually have a lower risk of ovarian cancer. The longer you use the pills, the lower your risk. However, oral contraceptive use is also associated with an increased risk of other types of cancer, including breast and cervical, among others.
Researchers have identified the risk factors above, but a definitive cause of ovarian cancer isn’t yet known. One theory is that ovulation frequency may impact ovarian cancer risk. People who ovulate less often may have a lower risk than those who ovulate more. Another theory suggests male hormones, or androgens, can cause ovarian cancer.
These theories and others remain unproven. However, researchers have identified two common themes in ovarian cancer. Both are related to a person’s genes.
Inherited genetic mutations
Individuals who have the BRCA1 and BRCA2 gene mutations have an increased risk of developing ovarian cancer. Other mutated genes may also impact a person’s ovarian cancer risk.
Acquired genetic mutations
Another theory is that a person’s DNA can be altered during their lifetime, and these mutations can increase their risk for ovarian cancer. Environmental impacts, radiation, or exposure to cancer-causing chemicals or substances may cause these mutations.
However, researchers haven’t yet identified a common link between these acquired genetic mutations and an individual’s risk for ovarian cancer.
While early-stage ovarian cancer does have symptoms, they can often be mistaken for benign conditions like constipation or irritable bowel syndrome. The cancer often progresses to advanced stage before it’s finally detected and diagnosed.
In almost all cases, ovarian cancers that are detected early can be treated successfully.
Symptoms of ovarian cancer include:
- changes in bowel habits, including frequent constipation
- abdominal bloating and swelling
- frequently urinating or feeling the need to urinate urgently
- feeling full quickly when eating
- unexplained weight loss
- general discomfort in your pelvic area
- pain during sexual intercourse
- upset stomach
- general fatigue
- changes in your menstrual cycle
When these symptoms are caused by ovarian cancer, they’re usually persistent and different from what you normally experience. If you have these symptoms more than 12 times in a month, you should speak with your gynecologist.
Tests and diagnosis
In order to diagnose ovarian cancer or to exclude it as a cause for your symptoms, your doctor will conduct a thorough examination.
During the physical exam, your doctor will ask you about the symptoms you’ve been experiencing and any family history of diseases that may impact your personal health. Doctors also have a number of tests they may use for diagnosis, including:
- Imaging tests. Your doctor may request one or more imaging tests. These tests include ultrasounds, CT scans, MRIs, and PET scans. If your doctor suspects you have a tumor, these tests can help determine where the tumor is, how large it has grown, and the cancer stage.
- Blood tests. Certain ovarian cancers release a protein called CA-125. Blood tests can detect the presence of this protein.
- Biopsy. In order to further test any suspicious spots or tumors, your doctor may remove a sample of tissue from your abdomen or pelvis in what’s called a biopsy. It allows your doctor to check for the presence of ovarian cancer.
If these tests confirm their suspicions and you do have cancer, your doctor may choose to perform surgery to remove the cancerous area.
After an individual is diagnosed with ovarian cancer, doctors try to determine how much and how far it has spread in a process called staging. There are four stages of ovarian cancer, and they represent where the cancer cells are located. Some of the later sub-stages are determined by tumor size as well.
In order to determine a cancer’s stage, your doctor will take several tissue samples from your ovaries, pelvis, and abdomen. If cancer is detected in any or all of the samples, your doctor can determine how far it has spread and advanced.
- Stage 1: Ovarian cancer in stage 1 is contained to one or both ovaries. It hasn’t spread to nearby lymph nodes.
- Stage 2: Ovarian cancer in stage 2 is in one or both ovaries and has spread to other organs in the pelvis. These organs might include the uterus, bladder, rectum, or fallopian tubes.
- Stage 3: Ovarian cancer in stage 3 has spread beyond the ovaries and pelvis, and into the abdomen, abdominal lining, or nearby lymph nodes.
- Stage 4: Stage 4 ovarian cancer is the terminal stage of ovarian cancer. Cancer in this stage has spread beyond the abdomen. It may have reached the spleen, lungs, or liver.
Treatment options for ovarian cancer depend on its stage and your overall health. Usually, the main types of treatment involve surgery and chemotherapy.
Surgery is the primary treatment for ovarian cancer. Removing the ovaries and fallopian tubes can treat most early-stage cases of ovarian cancer. If the cancer has spread into the pelvis, the uterus also may need to be removed. Neighboring lymph nodes and abdominal tissue may also need removal.
Later-stage ovarian cancer that has spread into the abdomen may require additional surgeries for cancerous organs or tissues.
If you’ve been diagnosed with ovarian cancer and you plan to have children, surgery may still be an option. Depending on your cancer and how far it has spread, your doctor may only need to remove one ovary.
In some cases, chemotherapy is the initial treatment option. Chemotherapy is a kind of drug therapy designed to destroy any rapidly dividing cells in the body, including cancer cells. Chemotherapy is sometimes used in conjunction with other treatments, including surgery.
Alternative ovarian cancer treatments
There are additional treatments your doctor may recommend for you, including hormone therapy and radiation therapy.
- Hormone therapy. Some types of ovarian cancers are sensitive to estrogen. Medications can block the production of estrogen or prevent the body from responding to it. This treatment may slow and possibly stop the growth of the cancer.
- Radiation therapy. In radiation therapy, X-ray or particle beams target and kill cancer cells in areas where the cancer has spread. It’s often used in conjunction with surgery.
It may be useful to understand your own prognosis by using the perspective and experience of others in similar situations. According to the American Cancer Society, doctors often use survival rates to discuss your prognosis.
The 5-year survival rate for all types of ovarian cancer is 45 percent.
People diagnosed before age 65 have a higher survival rate than older individuals. Those diagnosed with early-stage ovarian cancer — specifically, stage 1 ovarian cancer — have a 5-year survival rate of 92 percent.
Unfortunately, only 15 percent of ovarian cancers are diagnosed at this early stage.
Survival rates are broken down depending on the type of ovarian cancer: